As is well known, when a band-like glass ribbon is formed by a down-draw method or the like, selvage portions thicker than a central portion of the glass ribbon are formed at both ends thereof in a width direction. Thus, when the glass ribbon is rolled into a roll shape so as to manufacture a glass roll, the selvage portions are usually cut in order to prevent a diameter thereof from being improperly increased because of the thickness of each of the selvage portions.
For example, a method disclosed in Patent Literature 1 is publicly known as a method of cutting the selvage portions. The method disclosed in Patent Literature 1 utilizes a so-called laser cleaving method. A laser is radiated along a boundary between the central portion and each of the selvage portions of the glass ribbon in the width direction, to thereby form a heated portion in the glass ribbon. Then, the heated portion is cooled with refrigerant following the laser. Then, due to a thermal stress generated at this time, initial cracks formed at end portions of the glass ribbon in a longitudinal direction are propagated, to thereby cut the selvage portions.